This invention relates to a communication system having improved line pooling arrangements.
In situations where many stations may share access to a common pool of lines such as WATS lines, tie trunks, FX lines, or "outside" lines, it is desirable for the subscriber to determine prior to going off-hook whether or not there is an available line in the pool. Presently this information is available to central attendants who typically control access to pooled lines for a group of stations. In situations where it is desired to eliminate the attendant operation, it is desirable to provide each station having access to the pool with information concerning the busy-idle condition of the pool without requiring the station to first request service from the pool.
A further problem is to optimize the efficiency of the line pool such that utilization of the pooled lines is increased.
Increased utilization might be attempted by permitting a group of lines to be used as a pool for outgoing service from the communication system to the local central office, and, in addition, as a Listed Directory Number pool for use by the Central Office as the hunting group to the communication system. Such lines would then appear at the Central Answering Position for incoming business calls. A problem arises if such lines do not have glare protection protocol implemented on a per-trunk basis. Incoming calls may be inadvertently answered by a station attempting to seize an idle outgoing line.
These problems are compounded in situations where lines are available for individual use, but could also be available for "pooled" use if the need arose. Since each telephone station set having access to a pooled group of lines has different "other" lines appearing on the other buttons, simply combining the lines at the other buttons with the pooled group of lines would lead to confusion and improper telephone line usage.
Accordingly, it is a general object of our invention to provide a communication system having a high usage of common lines while also providing busy-idle indications of the lines in the pool prior to a subscriber going off-hook.